On Jan 14, 2009, at 11:15 PM, Ken Williams wrote:
I am trying to configure a dts file for the pci subsystem of a
MPC8540 based system.
I am expecting (hoping) that the value specified in the interrupts
property (98 in this example)
will be used as the virtual interrupt number and that I can later do
a request_irq using that number.
The .dts deals with physical interrupt numbers. Virtual IRQs is a
linux concept.
kernel: 2.6.26.3
The board level configuration is:
ADR29 connected to IDSEL
using INTA# only
The PCI interrupt is connected to external IRQ2
What I see is that inside irq_create_mapping, a call to
irq_find_mapping produces a null virq,
so irq_alloc_virt is called and comes back with x12. Can I assign
the number to 98 (x62)
using the dts? Any help would be greatly appreciated.
Do you want INTA# or the PCI error interrupt?
I'm guessing INT A#.
Here's an example from the mpc8540ads.dts:
pci0: p...@e0008000 {
cell-index = <0>;
interrupt-map-mask = <0xf800 0x0 0x0 0x7>;
interrupt-map = <
...
/* IDSEL 0x03 */
0x1800 0x0 0x0 0x1 &mpic 0x4 0x1
0x1800 0x0 0x0 0x2 &mpic 0x1 0x1
0x1800 0x0 0x0 0x3 &mpic 0x2 0x1
0x1800 0x0 0x0 0x4 &mpic 0x3 0x1
...
So the interrupt-map here deals w/PCI INTA# to INTD#.
(0x1800 0x0 0x0) (0x1) &mpic ((0x4) (0x1))
(pci address) (intA) pic-handle (pic HW IRQ) (irq sense info)
So to decode the example we have for IDSEL 0x03:
INTA: irq 4
INTB: irq 1
INTC: irq 2
INTD: irq 3
If you have a proper PCI driver in linux you shouldn't have to deal
with virtual IRQs at all.
- k
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